Wheel motor with rotating outer rotor转让专利
申请号 : US12551065
文献号 : US08476794B2
文献日 : 2013-07-02
发明人 : Velayutham Kadal Amutham
申请人 : Velayutham Kadal Amutham
摘要 :
权利要求 :
The invention claimed is:
说明书 :
The present application claims priority under 35 U.S.C. §119(d) to a corresponding patent application filed in India and having application number 1226/CHE/2009, filed on May 27, 2009, the entire contents of which are herein incorporated by reference.
Due to continued increases in the price of petroleum-based fuels, and concerns about by-products of burning petroleum-based fuels, electric and hybrid cars have become more popular with purchasers and more economical as well.
An electric car is a type of alternative fuel vehicle that utilizes an electric motor and motor controller instead of an internal combustion engine. A hybrid car is a type of alternative fuel car that includes both an electric motor or motors and an internal combustion engine. Currently, in most cases, electrical power is stored and derived from battery packs carried on board the vehicle. Fuel cells are also being used to power electrical motors.
In a pure electric vehicle, with no corresponding internal combustion engine, an electric engine replaces the internal combustion engine, providing a central power plant to provide power to a mechanical distribution system (a transmission) that then transfers the power to disparately placed wheels.
A similar system is used in hybrid vehicles, with the exception that both an electric motor and an internal combustion motor (albeit smaller than an internal combustion motor for an internal combustion-only vehicle) work together to perform the function of the traditional internal combustion motor. As in the case of the pure electric vehicle, a mechanical distribution system is utilized to transfer power from the centralized motor compartment to the disparate positions of the wheels.
In a conventional electric motor centralized at an engine compartment, the outer casing (the stator) is stationary while a rotating portion inside the stator (the rotor) rotates to generate mechanical energy. The transmission of the mechanical energy from the electrical engine in the centrally placed engine compartment of the vehicle to remote load locations at the wheels introduces losses into the system that reduce the efficiency of the electrical vehicle, and thereby decreases the overall range of an electrical vehicle.
Accordingly, advances in electric vehicle design are needed to further improve energy efficiency and reduce manufacturing and/or total ownership costs so as to increase the availability of electric and hybrid vehicles to consumers around the world.
Disclosed herein is an in-wheel motor comprising an inner stationary stator including a plurality of magnets having windings, the magnets arranged at an outer circumference of the stator, an outer rotor surrounding the inner stator and including a plurality of magnets arranged at a circumference of the rotor, and a bearing layer positioned radially between the stator and the rotor for allowing rotational movement of the rotor relative to the stator, and for distributing forces applied to the outer rotor. A plurality of switches may be arranged correspondingly to the plurality of windings, and a controller may be disposed for applying a switching pattern to the switches to cause the rotor to rotate in a first or second axial direction.
A speed of the rotor may be controlled by varying a frequency of the switching pattern, and a torque of the rotor may be controlled by varying a pulse width of the switching pattern. An encoder may be attached to the rotor to determine a current position of the magnets on the rotor relative to the windings of the stator to aid in determining a proper switching pattern to apply to the switches.
The bearing layer may be comprised of bearings. In one example, the bearings could be a plurality of rolling ball-bearings.
The disclosed in-wheel motor could be used as a wheel on a train so as to cause the rotor to rotate over a metal rail. Alternately, a rubber tire may be attached to an outer circumference of the rotor to allow the wheel to be used on a roadway material such as pavement or cement.
Also disclosed herein is an in-wheel motor having an inner stationary stator including a plurality of magnets including windings, the magnets arranged at an outer circumference of the stator, an inner support ring coupled to the magnets and extending in a direction parallel to a central axis of the in-wheel motor away from the magnets, an outer rotor surrounding the inner stator and including a plurality of magnets arranged at a circumference of the stator, a rotor projection portion extending in the direction parallel to the central axis of the in-wheel motor so as to surround the inner support ring; and a bearing layer positioned radially between the inner support ring of the stator and the projection portion of the rotor allowing rotational movement of the rotor relative to the stator, and for distributing forces applied to the outer rotor.
In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the Figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.
The mechanical support element 102 could be formed in the shape of a ring, as shown in
A plurality of electromagnets 106 are placed along an outer circumference of the mechanical support 102 and stator 104. Although
In other example embodiments, different shaped electromagnetic cores could also be used, including, for example, a bar-shaped, an F-shaped, or a C-shaped core. An advantage of the E-core is that it provides substantial room to bring in high current lead wires, and provides good heat dissipation. The E-shaped core 202 could be formed of an iron alloy, a cobalt alloy, ferrite, or any other suitable material. While
Returning to
As set forth in
Where the relative rotor 310 and stator 304 are in the positions shown in
A braking operation can also be implemented to cause an already rotating rotor 310 to slow down and/or stop. For example, we can assume that the rotor 310 of in-wheel motor 300 is already moving in a clockwise direction, and that
In an example embodiment, variation of the frequency of the pulses in the timing diagram of
The bearing 114 can support a radial load applied to the bearings from a vehicle attached to the wheel motor, and can support a thrust load applied during vehicle cornering. In the case of rolling element bearings, the bearings may be made from steel or stainless steel. Depending on the weight requirements of the application and bearings, other compositions such as polymers or ceramics could also be used. A lubricant such as grease or oil may be provided to decrease an amount of friction generated in the bearing 114. Additionally, retainer rings or grooves may be provided on the rotor 110 or the stator 104 to maintain the bearings 114 in a proper position.
Although not shown in the Figures, a tire may be attached directly to an outer surface of the rotor 110. The tire, for example, may be comprised of a rubber or rubber/composite compound, and may be inflated with air to maintain a particular tire pressure. The tire may include additional load-supporting sidewalls or plastic load-bearing inserts to allow the time to run safely for a limited range at a limited speed. In this embodiment, the rotor 110 may be formed so as to include flanges at outside edges of the outer surface that the tire may interface and bond width to secure the tire and rotor 110 together.
Alternately, although not shown, a cover may be provided circumferentially over the outside of the rotor 110 in order to protect the magnets 112. Any additional support structure may be provided between the rotor 110 and the cover, such as a solid support, a plurality of spokes, or any other structure that can support a large weight load such as a locomotive. An outer surface of the cover may then directly contact a metal rail in operation so that rotation of the rotor 110 causes a locomotive or similar vehicle to move in a forward or reverse direction. In such an embodiment, the wheel may include a profile and flange on an inside portion to facilitate maintaining the wheel on the rail. In other example embodiments the rotor 110 may employ an additional mechanical support to a circumferential rim upon which a tire can be mounted. For example, the in-wheel motor may be implemented within a hub from which spokes extend radially outward to a rim with appropriate flanges to mount a tire. The hub includes rotor magnets (see in
Specifically, for example, a plurality of in-wheel motors 100 or 700 could be provided at predetermined vehicle locations. At rest, none of the switches S1-S6 are energized. An encoder provided on the wheel or coupled to the wheel provides a position indication of the electromagnets 106 relative to the magnets 112 to a controller 502. The controller 502 may then determine which electromagnets 106 are properly offset from corresponding magnets so as to avoid a driving deadlock situation. Once the controller 502 determines which electromagnets 106 to begin driving with, the controller 502 begins outputting a pulse pattern similar to that of
As noted earlier, a variation in the frequency of the switching pattern applied may be used to vary the speed of the rotor, while a variation in the pulse width of the switching pattern may be used to vary a torque applied to the rotor 110. The switching pattern may continue at one or more frequencies until a braking operation is implemented. In order to brake, the controller 502 will apply a braking switching pattern to the switches that will result in an electromagnet force applied to the magnets 112 in a rotational direction opposite the current rotational direction of the rotor. The braking switching pattern may continue until the rotor 110 reaches a desired speed, or until the rotor reaches a complete stop.
In this manner, an in-wheel motor 900 can be provided that directly drives an outer tire or cover, eliminating transmission losses from a centralized engine, decreasing the overall weight of the vehicle, and increasing a range of an electric vehicle incorporating the in-wheel motor. Additionally, during vehicle braking, the in-wheel motor can provide regenerative power to pump energy back to a storage battery for use during a subsequent acceleration, further increasing the range of the electric vehicle incorporating the in-wheel motor. This also increases space efficiency since no separate centralized space is required for the motor.
The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. Functionally equivalent methods and apparatuses within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that this disclosure is not limited to particular methods, reagents, compounds compositions or biological systems, which can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present.
For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.).
In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”
As will be understood by one skilled in the art, for any and all purposes, such as in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as “up to,” “at least,” “greater than,” “less than,” and the like include the number recited and refer to ranges which can be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member. Thus, for example, a group having 1-3 cells refers to groups having 1, 2, or 3 cells. Similarly, a group having 1-5 cells refers to groups having 1, 2, 3, 4, or 5 cells, and so forth.
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.